M21- Luxury Rainbow Watch.

Basic Information

• Case Size (L × W × H): 51.9 × 50.9 × 12.1 mm
• Weight: 111 g
• Case & Bezel Material: Carbon / Stainless Steel
• Band: Resin Band

Durability & Construction

• Shock Resistance: TRIPLE G RESIST (Shock resistant, Centrifugal force resistant, Vibration resistant)
• Structure: Carbon Core Guard
• Water Resistance: 200 meters

Time Adjustment & Power Supply

• Time Adjustment: Radio-controlled Watch; Multi Band 6
• Power Supply: Tough Solar (Solar powered)

Smartphone Link & App Connectivity

• Smartphone Link: Wireless Bluetooth® Connectivity
• Compatible App: CASIO WATCHES
• App Features:
  • Auto Time Adjustment
  • Easy Watch Settings
  • Approximately 300 World Time Cities
  • Time & Place Function
  • Watch Status Display
  • Self-check Function
  • Phone Finder

Exterior & Design

• Glass: Sapphire Crystal with Anti-Reflective Coating
• Crown: Screw Lock Crown
• Surface Treatment:
  • Blue Ion-Plated Bezel
  • Purple Ion-Plated Bezel
• Compatible Band Size: 145 to 215 mm
• Other Features: Neobrite (Luminous Coating)

Watch Features

World Time & Dual Time

• Time Zones: 27 Time Zones
• Functions: Home City Time Swapping, Auto Summer Time (DST) Switching

Stopwatch

• Measurement: 1-Second Stopwatch
• Capacity: 23 hours, 59 minutes, 59 seconds
• Modes: Elapsed Time, Split Time

Countdown Timer

• Unit: 1 Second
• Range: 1 Minute to 24 Hours
• Adjustable in 1-Second Increments

Alarm & Hourly Signal

• Daily Alarm

Illumination

• Light Type: LED Super Illuminator
• Afterglow: Yes
• Light Color: White LED

Calendar & Timekeeping

• Full Auto-Calendar: Until Year 2099
• Hand Home Position Correction: Auto Adjustment

Energy-Saving & Battery Features

• Power Saving Mode: Hands Stop When Left in Dark
• Battery Level Indicator: Yes
• Battery Life:
  • Normal Use: 5 Months (Without Light Exposure)
  • Power-Saving Mode: 18 Months (Stored in Darkness After Full Charge)

Accuracy

• Precision: ±15 Seconds per Month (Without Signal Calibration)

Radio Signal Time Calibration

Auto & Manual Time Reception

• Auto Reception: Up to 6 Times a Day (5 Times for China Signal)
• Manual Reception: Available
• Latest Signal Reception Display

Calibration Signal Stations & Frequencies

• DCF77 (Germany): 77.5 kHz
• MSF (England): 60.0 kHz
• WWVB (USA): 60.0 kHz
• JJY (Japan): 40.0 kHz (Fukushima) / 60.0 kHz (Fukuoka/Saga)
• BPC (China): 68.5 kHz